Train control system



Dec. 8, 931.

H. B. MILLER ET AL TRAIN CONTROL SYSTEM Original Filed Sept. 2, 1926 lio Patented Dec. 8, 1931 narran? srArss PATENT-f OFFICE# HARVEY n. MILLER, on s'rAUNTO'N, VIRGINIA, AND PHILIP X. RICE, or DANVILLE, ILLINOIS, Assienons V'ro THE MILLER TRAIN.ooN'rROL..ooR1 ORATIoN, or srAUnron, VIRGINIA, A CORPORATION or f VIRGINIA I TRAIN .CONTROL SYSTEM Application filed. September 2, 1926, Serial iNo. 133,260. RenewedAvprl 28, 1931.v

rll`liis invention relates to train control systems of the intermittent induction type,` as disclosed in the copending applications of ihilip X. Rice, Serial Numbers '106,47 8, filed May 3rd, 1926, and 714,962, tiled May 21st,

` in the systems shown in the copendin-g applications above identified, there is disclosed a pair of magnetizable train carried cores provided with primary and secondary windings, the primary winding beingconnected to a source of alternating current whereby the flow of magnetic iux betweenthe cores is adapted to in duce a current in the secondary core and coil, the current in the secondary being utilized for maintaining Van electro.- pneumatic valve in closed position.. The apparatus is` associated with and adapted to influenced by track-side inductors rwhereby the flow of magnetic flux may be interrupted or reduced-.in such a manner as to reduce the alternating current in the"y secondary circuit, and thus permit the electro-pneumatic valve to open, this valve having-a norf maill bias to open position. Considerable torce is necessary to maintain the electropneumatic valve in closed position, and consequentiy considerable secondary vcurrent is required for thiswork.

in the system disclosed in copending ap,- piicaiion SerialNo. 106,478, above referred to, there is disclosed means whereby the engineer, by manual operation of a switch, may

forestall the Voperation oi' kthe apparatus,

provided t'liefswitch referred to is closed be` iorethe tr in carried device passes over an open circuitedtrack inductor. The manual# ly controlled switch is adapted to 'supply current directif,7 from Vthe source of alternating current to the electro-pneumatic valve', whereby the latter will be retained in closed position when the train device passes over an open circuited track-side inductor which uormaliy would ei'iect a suii'icient reduction in the secondary current to permit the electropneuinatic valve to open. f Y

in important object of thepresentinvention is to' provide a system of the character generally* outlined above f wherein "af second source of current is employcdfor maintain'- tance above the track-side ing the electro-pneumatic valve in closed position, the current from the secondary coil of the train shoe being utilized merely for closing a relay to complete thecirouit from the second current. source tothe electro-pneumatic valve, whereby considerable economy in the consumption of current is effected inasmuch asa weaker current in the secondary circuit may be utilized.

' A further object of the invention is to provide a systemof the character just mentioned.

wherein the reduction ot the current necessary in thesecondary circuit is adapted to render-the system more sensitive thus Vpermitting "the primary and( secondary cores or shoes to be arranged a substantial disinductor to be inliuenced thereby. 1 f

A further object of the invention isto provide a train cont-rol vsystem provided with meansof-tlie character previously referred to whereby the engineer may forestall the opening of the electro-pneumatic valve when passing over, an open circuited inductor, rand wherein the engineer is further permitted to after-stall theoperation of the valve provided he takes suitable action Withinra limited time after the locomotive passes over an open ciicuited inductor.

A further object is to provide a forestalling device'including a circuit having a portion y associated with and adapted to be controlled byA a time device whereby the engineerv may close a suitable yswitchv to directlyY connect the source yot alternating currentto a relay to maintain the electro-pneumatic lvalve in closed position, the time device being adapted to prevent'the closing of the circuit referred to after a given interval of time.

- A further object is'to provide a train control system wherein audible warning isgiven to the engineer when passingover an opencircuited inductor whereby he'may, if he so de? sir/es, prevent the operation of the system by closing a suitable ,switch within a given length of time after the locomotive passes over the inductoizl i .A further ob'eot isto provide means asso'- Vciated with ya train control system of' the .2,5 movablejdownwardly by gravity to open povso ' to the wire 27, while the wire 18 is connected of the electro-pneumatic valve may be effected after the speed of the train has been reduced to a predetermined limit.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the drawing, the single figure is a diagrammatic representation of the train carriedcircuit.

Referring toithe drawing, the numeral 10- designates a suitable alternator having take-1 off terminals 11 and 12. The terminal 11 is connected to a second terminal 13, and a wire 14 is connectedto one end of the primary coil 12 of the shoe 13. The other end of the primary coil is connectedr to the terminal 12 through wires 15 and 16. AThe-shoe also e1nploys a secondary coil 14 connected to leads 17 and 18. lThe shoe employed may be of any suitabletype, suchas the types shown in the copending applications above referred to, and need not be described in detail.

The numeral19 designates a manually controlled switch as a whole which is normally Ysition, as will become apparent. The switch 19 includes a stem 2O to which are connected switcharms 21,22 and 23, the switchv arms being-suitably insulated from the stem. Contacts 24 and 25 are arranged on opposite sides of the arm 21 and are adapted to contact therewith. A wire 26 is connected to the contact 25, while a wire 27 is connected between -the contact 24v and one end of' the coils of a relay '28'.v Asshown, the wire 17, connected to the secondary coil of the shoe, is connected `to theoppositeend lof the coils of the relay aS at 29. i

The relay is provided with an armature 30 provided with means (not shown) whereby it has a-normal bias to open position; The armature is provided with a switch armr31 which normally contacts .with a stationary contact 32. Thexarm 31- is connected by a Vwi-'re 33 withone side of av suitablesource of current. 34. From the yopposite side of the 'source 34, a wire 35leads to a solenoid36, the lead 37 `from the opposite side ofthe solenoid beingconnected toi-the 'stationary contact 32.

It will be apparent that the` relay 28 is adapted to Abepnormally energized by current induced in the secondary coil of the shoe, whereby current is normally supplied from thefsource 34 to the solenoid: 36 to maintain the latter. energized. The solenoid is `provided with ar movable core 37 having a valve 3,8'alrranged at its-upper enc vThis* valve adapted to normally closeanfopening39 in ,achamber' 40. f' ir `As shown, a pipe 41 is connected between the chamber40 anda whistle or other audible signal 42,` whereby the signal, will be .operated whenV ,liuidj pressure is supplied end of the pipe 46 being connected to a suitable source of Afluid pressure supply. A

`piston 47 is arranged to reciprocate in the cylinder between the pipe 46 and the reservoir 43. The piston 47 is provided with 'a leakage vport 43 affording restricted communication between the opposite ends of thc cylinder 45 for a purpose to be described. The piston 47 is mounted upon the lower end of a piston rod 49 the upper end of which projects through'the upper end of the cylinder and a substantial distance therebeyond. A preferably cylindrical contact 50 is carried by the piston rod and is insulated therefrom as at 51. The contact 50 is adapted to establish electrical communication either between a contact 52 and a contact 53, or between the latter Contact and a third contact 5,4. The upper end of the piston rod 49 is adapted to control a swinging switch arm 55, the latter being movable downwardly bygravity and normally supported by the upper end of the piston rod. The arm 55 contacts with a movable contact 56 connected to a lead wire 57-and an adjustable set screw 57 vis adapted to limit the downward movement of the contact 56. The opposite end of the wire 57 is connected yto a swinging switch arm 58 which is supported upon the upper end of an extension 59 which may be formed integral with the core 37. The arm 58 normally establishes electricalconnection with a contact 60 connected to one end of a wire 61. One side of the source of current 62 is connected to the wire 61 through a lead wire 63, the wire 61 also being connected to theswinging arm 55 as shown.

In the drawing we have diagrammatically shown an electro-pneumatic valve 64. This valve includes a pipe 65 normally closed by a. valve 66 carried by the upper end of an armature 67. The valve is normally maintained in closed position by a solenoidv67. The valve 64 is adapted to control the air rbrake system according to the usual. practice. The solenoid 67 is provided with a lead wire 68, the opposite end of this wire being connected to the wire 57. The oppo site end of the solenoid winding is connected by a wire 69 to the opposite side of the source of current 62.

Contacts 7 0 and 71 are' associated with the Varm 22 of the switch 19. A wire 72 connects the contact 70 with the wires 15 and 16,

vwhile kthe contact 71 is connected through wires 73 and 74, with the contact 52..` The wire 73 is also connected to a suitablev condenser 75, the opposite side of which is con# nected to the contact 54 through a wire 76. Contacts 77 and-78are associated with the arm 23 and are adapted to contact therewith. A wir-e 79 connects the contact 7 8v with the wire 72, while the contact 77 is grounded as at 80 through a wire 81.

Means are provided whereby the4 valve 64 may be reset after the solenoid 67 has been deenergized. This means includes a speed governor 82, the arms of which are adapted to contact with stationary contacts 83 and 84. A wire 85 connects the contact-83 to a ground 86. The other contact 84, is connectcd by a wire 87 to one side oi' a condenser 88 of suitable capacity, the opposite endk of this condenser being' connected by a lead wire 89 to a wire 90. The latter wire is connected at one end to the Contact 53 and the opposite end of vthe wire 90 is connected to the wire 18 and relay coils 28. Y

The operation of the systemis as follows:

Current is supplied to the primary coil 12 of the shoe through wires 14 and 15 from the alternator 10. The arrangement of the core of the shoe, as previously explained, is such that ma gnetic flux threads the secondary portion of the core from the primary portion, thus inducing a current in the secondary winding 14. This induced current flows through wires 17 and27 'to the relay 28 and thence back to the secondary winding through leads 29 and 18. The inducedcurrent maybe relatively weak, but will have sufficient strength tov retain the armature 30 in closed position whereby the switch varm 31 will be electrically connected to the contact 32. Current will then flow from the source 34', through wire 33 and switch arm 31 to contact 32. thence through `wire 37 to the winding` of the solenoid 36, and thence back to the source of current 34 through wire 35. Thus it will be apparent thatv the solenoid v36 normally will be energized to retain its core in upper position to hold the valve 38 in closed position. thus preventing,` the passage of pressure fluid from thereservoir 43 to the chamber 40.' When escape of fiuid from the reservoir 43v is prevented,j the port 48 serves to'establish equal pressures on op# posite sides of the piston 47 inthe cylinder 45. Since the effective area of theA lower face of the piston is ,area-ter than that of the upper face, it will be apparent that the pis-- ton 47 normally will be moved vupwardly to A. nection will be establishedt across the 'coniv tacts 52 and 53 by means of theV contact 50'.

the position shown, whereby electric'alfconA With the parts in the position/shown,` it will be vapparent that current will flow from the source 62 through wire 63, and through either wirel 61 orswitch arm 55. Both the latter elements are normally electrically connected to the wire 68, and thus current'will be'supplied to the solenoid 67 current returning tromy the solenoid to the source 62 through wir-e 69. Thus the valve 66 will be maintained closed and the braking system of thevehicle will remain linoperative.permitting the ve- If the inductor coil is in -80 interrupted or `reduced thus affecting the re- Y lay 28 and permitting the armature thereof to open. This actionobviously breaks the electrical rconnection'between switch arm 31 and conta'ct32 and hence the solenoidv 36 will be de'cnerqized, permitting its armaturel to drop. The valve 38 then will be opened permitting the escape of pressure fluid from the reservoir 43 to the chamber 40, and the signal 42 will be sounded. This action further decreases the pressure in the lower end of cylinder 45 and since this pressure' decrease takes place slightly faster than the pressure can be built up through the escape of fluid y through the port 48, it will be apparent that the piston 47 will slowly drop. Movement of' the piston downwardlypermits the movable contact 56 to move downwardly until its movement is 1 arrested by the set screw 57 whereupon `further downward movement of the piston breaks theelectrical connection between the switch arm and contact 56.

Since the switch arm 58 -will have been disconnected from the contact -60 uponthe previously described deenergization of the sole-v noid 36, nocurrent will be supplied from the source 62, to the solenoid 67 and hence the valve 66 will open thus setting the brakes of the vehicle and causin'git to stop. y

Means are provided whereby the engineer may forestall. the operation of the valve 66 before the vehicle passes over a track inductor. By lifting' the switch 19, the" arms 21 and 22 may be caused to establish connection with their respective contacts. Current -will then be supplied from terminal 11, through wire 26, Contact 25, arm 21 and contact 24,

and thence thro-ugh wire 27 to coils 28. From the relay 28 current {iows through wire 90 to Contact' 53, across contact 50 to contact 52, and thence back to the other terminal of the alternator through wire 73, 'Contact 71. arm contact 70 and wires l6`and 72. Thus it will'be apparent that current will be supplied directli/v to the coi-ls ,28 rfrom the alternator whereby a decrease in current in the secondary core of the shoe when` passing over'an open circuited inductor willfnot alect the permits a balanced pressure to be reestabcoils 28and the circuits supplied with current'from the sources 34 and 62 will remain closed "and the vehicle is permitted to proceed. f

\Under,some conditions, as during foggy i-veather, itis difcult for the engineer' to see the visible block signal before the shoe passes over theinducton'and accordingly we provide means whereby the engineer may atenstall the operation et the electropneumatic valve, provided lhe takes proper steps within a limited'time after the vehicle has passed over the inductor.y As previously stated, a? ,suit cient reduction in current to permit the armature 30 t'o open causes the circuit of the source 34 to be opened thus deenergizing the solenoid 36. v'This action causes the two results previously referred to, namely the sounding oi the signal 42 and the slow lowering ci the piston 47. Down'ward movement of the pis ton causes the Contact v50 to bridge across the contacts V53 and 54 before the connection is broken between contacts 55 and 56. lf the engineer desires to prevent the application of the brakes, he necessarily must take the proper steps before the contact 50 passes downwardly beyond the contact 53. Under sach conditions `upward movement of the switch 19 closes a circuit from the alternator substantially in the manner previously described in connection with the forest-ailing ot the operation o1" the pneumatic valve. lnstead of current passing from the contact 53 to the contact 52, however, it will pass to the contactv 54, and thence through wire 76 and condenser 75, to wire 73 ,from whichthe current returns to the alternator in' the manner previously described. It will be obvious that the windings of the relay Y28 possess substantial inductive reactance, and accordingly the current from the alternator is not snllicient to' reset the armature 30 unless this inductive reactance is neutralized. Accordingly we provide the condenser 75 in circuit with the coils 28, andthe capacity` reactance 'of the condenser 75'is -suiiieient to overcome the inductive reactance of the relay windingswhereby the latter maybe suiiicientlyenergized to attract its armature and close the circuit of the source 34. VWhen the relay 28 is thus energized, the circuit will be closed between the source 34 and solenoid 36 whereby the armature of the latter will be moved upwardly to close the valve 38. This action prevents 'liar'- ther escape of fluid from the reservoir 43 and lished in the cylinder 45 whereupon the piston 47 will move upwardly to normal position without having broken the connection l between contacts 55 and56. Thnsit will be apparent that the brakes will be prevented from acting and the vehicle may proceed.

If the 'vehicle travels over the inductor without having the operation of the pneumatic` valve forestalled or after-stalled :it

will be apparent that the brakes will be applied due to the breaking of the circuits to the solenoid 64 and the Yconsequent release of air from the kbrake pipes. y The contact 50 thus will move downwardly beyond the contact 53 and the circuit through contacts 55 and 56 will be broken, thus making it impossible for the engineer to reset the solenoid 67 by operating the switch 19. Under such conditions, it is necessary for the engineer to wait until the vehicle has reached a miniinum or zero'speed whereby the contacts 83 and 84 will be connected to each other. At this time, as previously stated, the piston 47 will have moved downwardly a suflicient distanceto open the circuit between contacts and 56 and accordingly the brakes Vwill be set. As shown in the drawing, the arms 21 and 23 are adapted to establish connection with their respective contacts before the circuit may be established across the contacts 70 and 71. When the vehicle has been brought to a minimnmor zero'speed, the engineer may lift the switch 19 to close the circuit between the contacts 77 and 78. Under such conditions, current Iwill be supplied from the alternator to the wire 90, in the manner-,previously described, and this current `flows to wire 89, and thence tothe condenser 88 to wire 87 and Contact 84. The current'then flows through the governor arms 82 and vwire 85, to ground 86 andv ground 80. Current is returned to the alternator through wire 81, contact 77, arm 23, contact 78, and wires 79 and 16.V The reset condenser 88 is of substantially'the same capacity as the condenser 75, being adapted to neutralize the inductive reactance of the relay 28. Thus it will vbe apparent that itvwill be impossible for the engineer to reset the valve 66 through the circuit just described until the train has been brought to a minimum or zero speed. It will be apparent that an appreciable length of time is Vrequired for the piston 47 to move downwardly to break the connection between contacts 55 and 56, and similarly it requires a considerable interval of time to close the circuit between these members when the re'- set mechanism is operated. The 'switch 58 is provided inA order that the solenoid 64 may be quickly energized when the reset switch is closed without waiting for the piston 47 to moveupwardly to close the circuit between the contacts 55 and56. VV i In operation we prefer to arrange the cylinder 45 and associated elements in' such a manner that it requires approximately three seconds for the contact 50 to pass dov'vnward-V ly beyond the contact 53, this interval of time being given to permit the engineer to afterstall the operation of the relay if he sodesires.

From the foregoing it will'be apparent that relatively slight currents are sufficient to operate Vthe valvefmagnet 28, and accordingly iso size and arrangement of rparts may be lresort-V ed to without departing froml the spirit yof` the invention or the scope of thefsubjoined claims.

le claim: f

l. ln a train control system, a source of current, electrically operated `means normally energized to maintain it in operative position to permit the vehicle to proceed, circuits associated with said source of currentand'adapt- Ved to beinluenced under certainl track conn ditions to cause deenergization ofrsaid electrically operated means to influence the speed of the vehicle, at least oneof said circuits normally being inductively reactive, :said

source normally'beingineiiective for render-J ing said electrically operated means oper.y ative after it has been deenergized,`anfauxiliary circuit adapted to cause the energizationl of said electrically operated means by said source independentlyof track conditions and including capacity reactance adapted to neutralize the inductive reactance of one of said lirst named circuits, and time controlled means for breaking said auxiliary: circuit.

Y In a vtrain control system, a source ofA current, electrically operated means normally energized to maintain it in operative position. to permit the vehicle to proceed, circuits associated with said source of current and adapted to be iniiuenced undercertain-,track conditions to cause deenergization of said electrically operatedmeans to iniiuence the speed of the vehicle, atleast `one otsaid circuits being inductively reactive, saidsource;

being normally ineiective lfor rendering said. electrically operated means operative after it has been deenergized, a reset circuit .in-

cluding sufficient capacity reactance to neutralize the inductive reactance of one of said lirstmentioned circuits, and speed respon sive means adapted to complete said reset, circuit when the speed of the vehicle vis `rethe vehicle under certain track conditions, said source being-normallyl ineffective for operating said electro-magnetic means after it Ahas become deenergized, anauxiliary circuit, tuned to the Jfrequency of said source, for eperatingV said electro-magnetic =ineans alter its deenergizationfa manually controlled switch :in said auxiliary circuit, a

second switch adapted tocoinplete said-aux# iliary circuit when said manually controlled switch is closed, and. time controlled means t'or said' second named switch including a izfrcssure chamber adapted to be influenced by track conditionsto release pressure therefromunder certain track conditions whereby said second namedswitch' will be vrendered.

operable to open said auxiliary circuit'aiteran interval of time. w '1 At. Ina train kcontrolsystem, a source'of alternating current, train controlling means including `electro-inagnetic. :means f normally energized from said source'I to vpermit the -vehicle to proceed, a circuit influenced by track conditions andiadaptedfto control said electro-magnetic `means lwhereby .the latter ,"v

becomes vdeenergize'd to :apply the brakes .to the yvehicle underwcertain .track conditions, said source being normally ineffective :for causing operation of said electro-magnetic means after `it has becoinedeenergized, :an auxiliary circuit, tuned tothe y:frequency .of said source, for operating. saidVelectro-ni'agnetic, means after lits deenergizatioii, Vi a manually controlled switch in said auxiliarycircuit, control switch vadapted to complete said auxiliary circuit when :said manually controlled, switch is closed, afpiston` con-l nected to said control switch, .a `pressure chamber in which'said piston is. arranged', and vmeans for releasing pressure fromsaid. chamber `under certain .track conditionsL whereby it will be rendered operableztoopen said auxiliary circuit after .an interval bf time.fx v 5. In atrainfcontrol system, a source of `alternating current, traincontrolling means including electro-magnetic means `normally energized from-said source to perm-it the vehicle to-proceed,-a' circuit influenced by trackconditions and adapted to controlsaid electro-magnetic means Vwherebythe flatter becomes vdeenergized to apply the brakesof the vehicle 'under certain track conditions, said source being ineifective for-operating said electro-magnetic means after .it has ybecome deenergized, an auxiliary circuit, tuned to the frequency ofsaidsource, for operating said electro-magnetic meansafte'rits deenergization, anianually controlledlswitch in saidauxiliary circuit, acontrol switchadaptedto. complete said auxiliary circuit when said: manually controlled switch is closed, a piston connected to said switch, a pressure chainber `in whichsaidpiston is arranged, .means for lreleasing pressure 1 from-@Said chamber fia under certainl traiiic conditions whereby it will bej'rendered operable to open said auxiliary circuit after an interval of time, and a signal operable upon release of pressure from said chamber.

6. In a train control system, a source of current, train controlling means including electro-magnetic means normally energized to permit the vehicle to proceed, a circuit influenced by track conditions and adapted to control said'electro-magnetic means whereby the latter will vbecome deenergized to apply the brakes ofthe vehicle under certain track conditions, said current source being inefective for operating said electro-magnetic means after it has become deenergized, an. auxiliary circuit-adapted to render current from said source effective fory operating said electro-magnetic means, a manually controlled switch for said auxiliary circuit, a control switch adapted to complete said auxiliary circuit when said Vmanually controlled switch is closed, arpiston connected tol said control switch, said piston being provided with a port'extending therethrough, a cylinder in which said piston is adapted to reciprocate, a source of fluid pressure supply communicating with one end oi' said cylinder,

cuit and a secondary circuit adapted to beV inductively coupled, a source of alternating current for said primary circuit, a relay connected in said secondary circuitand having a normal lbias to open position, said relay being normally energized by induced current in said secondary Vcircuit and adapted to be deener'gizedV under certain track conditions to permit it to open, electro-pneumatic train control means,a source of current for said train control means, a switch connecting said second source to said train control means and adapted to be opened upon deenergization of said relay, and a time controlled switch operable to connect said source of alternating current directly to said relay.

y8. In a train control system, a primary circuit'and a secondary circuit adapted to be inductively coupled, a source of alternating current for said primary circuit,a relay connected in said secondary circuit and having anormal bias to open position, said relay normally being energized by induced current in said secondary circuit and adapted to be deenergized under certain track conditions to permit Iit to open, electrically operated train control means, a source of current for said train control means, a switch normally connecting said second source to said train control means, pneumatically operated means normally retaining said switch in closed position, and means controlled by the deenergization of said relay for rendering said pneumatically operated means inoperative. f

9.A In a train control system, a primary circ ypermit it to` open, electrically operated train controlling means, a source of current for said train control means, a switch connecting said source to said train controlling means, pneumatically operated means including a fluid pressurereservoir for retaining said switch in closed position, and means controlled by the deenergization of said relay for releasing pressure from said reservoir.

i0.. In a train control system, a primary circuit and as'econdary circuit adapted to be inductively coupled, a source of alternating current for said primary circuit, a relay connected in said'secondary circuit and having a normal bias Vto open position, said relay normally being energized byvinduced current in said secondary circuit and adapted to be deenergized under certain traffic conditions to permit it to open, electrically operated train controlling means, a source of current for said train controlling means, a switch connecting said second named source to said train controlling 'l means, pneumatically operated means including a fluid pressure reservoir for retaining said switch in closed position, means controlled by the deenergization of said relay or releasing pressure from said reservoir, and anlaudible signal adapted to be actuated upon the release of pressure `from said reservoir. l f

ll. In a train control'system, a primary circuitanda secondary circuit adapted to be inductively coupled, a source of alternating current o'r said primary circuit, a relay connected in said 'secondary circuit and having anormal-bias to open position, said relay normally being energized'by'induced current'in said secondary circuit and adapted to be deenergized under certain track conditions to permit it to open, electro-pneumatic train control means, a source of current for said'train control means, a switch connecting said, second named source to said train controlling means, a piston normally adapted to retain said `switch in closed position, a cylinder in' which said piston is adapted to reciprocate, means for supplying Huid pressure to one end of said cylinder to retain said switch in closed position, and Aelectrically operated means for releasing pressure from sai-d cylinder to permit said switch to be opened upon rdeenergization of said relay.

12. In atrain control system, a primary circuit and a secondary circuit adapted to be inductively coupled, a source of alternating current for said primary circuit, a relay connected in said secondarycircuit and having a normal bias to open position, saidrelay nor'- inally being` energized by induced current in said secondary circuit` and adapted. to be `dcenergized under certain control means, a train Acontrol means, iitch connecting said second named source to said train V control means, a, piston normallyadapted to retain said switch in closed position, a ylinder in which said piston is adaptedtcreciprocate, means for supplying fluid `pressure to said cylinder to retain said switch in closed piosition, a valve normally adaptedto prevent escape of fluid from said cylinder, and electro-magnetic means normally energized for retaining said valve in closed position,said electro-magnetic means being adapted to be deeneroised upon the opening' oi' said relay.

13. In a train control systenna primary circuit and a secondary circuit adapted to be inductively coupled, a source of alternating current for said primary circuit,.a relayv con-y nected in said secondary circuit and having a normal bias to open position, said relay normally being energized Kby induced current in said secondary circuit and adapted to be deenergized under certain track conditions to permit it to open, electro-pneumatic train control means, a source ci current for said train control means, a switch connecting said second named source to saidA train control ing circuit normally including said cont-act,

and a manually operable switch adapted to complete said forestalling circuit,.said last named circuit being adapted to be broken after a predetermined interval of time upon the release of pressure from said cylinder l/l. ln a train control system, a primary tracl: conditions toierinit it. to oven electro-oneun'iatic .train l i i source of currentfor saidk control-means, a source 'of current for said train control means, a switch connecting said second named source to said train control means, a piston normally adapted to retain said switch in closed position, a cylinder in which said pistonV is adapted .to reciprocate, means for supplying fluid pressure tofsaid cylinder to retainsaid switch in closed position, a valve normally adapted to prevent escape of Huid from said cylinder, electromagnetic means normally 'energized' fori rctaining said valve infclosed position, said electi'o-magnetic means being adapted to be deenergized upon ythe opening of said relay, a'contact movable withsaid piston, afores'talling circuit normally includingsaid contact, a manually operable switch adapted to com-plete said forestalling circuit, said last named circuit being adapted to be broken upon movement of said contact, an afterstallingcircuit including in part said forestalling circuit, said after-stalling circuit also including saidcontact after the latter has no ved to break said forest-ailing circuit, and

manually controlled switch adapted to completer said after-stalling circuit.

l.. In a train control system, electricall operated means normally energized to maintain it in operative condition to permit the vehicle to proceed, intermittently operative means actuated under certain traiiic conditions to render said electrically operated means inoperative and thus to infiuence the speed of the vehicle,a pair of circuits associated with said electrically operated means, one ofsaid circuits being operative when closed' prior Vto the operation of said intermittently operative means for retaining said electrically operated means energized during such operation, the other circuit being adapted when closed within an interval of time after the operation of said means for restoring said electricallyoperated means to normal condition, and a common manually operable switch member vfor closing said circuits. a Y Y 1G. In a train control system, a source of current, electrically operated means normally energized from said source ito maintain it in operative condition to permit the vehicle to proceed, automatic means operative under certain traliic conditions to render saidelectrically operated means inoperative and thus to influence the speed ofthe vehicle, control means operative prior to the operation of said automatic means for rendering the latterineective for influencing the speed of the vehicle, .a second control means including in part said firstnamed control means and operable within aninter-val of time after the operationof said automatic means for restoring the normal condition-of said'electrically operated means, and-common manually operable means for both of said fcontrolmeans. q

nis

1.17. In a train control system, a source o alternating current, electrically operated means normally energized from said source to ymaintain it in operative condition to permit the vehicle to proceed, automatic means operable under certain trafic conditions to render said electrically operated means vinoperative and thus to-infiuence the speedV of the vehicle, a circuit adapted when closed to maintain said electrically operated means energized upon operation of said automatic means but being adapted to supply insufficient current to saidr electrically operated means to initially operate it, a circuit adapted when closed within an interval of time after operation of said automatic means to enengizey said electrically operated means, said last named circuit'being adapted to supply suilicient current to said electrically operated device to initially operate it, and common switch means for closing said circuits. 18. In a train Vcontrol system,a source of alternating current, electrically operated means normally energized from said source to maintain it in operative condition to permit the vehicle toY proceed, said Lmeans possessing a substantial degree of inductive reactance wherebycurrent from said source is insufficient to initially operate it, automatic means operative under certain trailic conditions to render said electrically operated means inoperative'and thus to influence the speed ot the vehicle, a circuit adapted when closed to maintain said electrically operated means energized upon operation of said automatic means but being adapted to supply insuilicient current to said electrically operated means` to initially operate it, a circuit adapted'whenrclosed within an interval ottime atteroperation of said automatic means to energize said electrically operated means, said last named circuit possessing suflicieiit capacity reactance to neutralize the inductive reactaiice of said electrically operated means whereby said last named circuit is adapted to supply suiiicient current to said electrically operated means to initially operate it, and common switch means for closing said circuits. f

19. In an automatic train control system, the combination of a car-carried apparatus comprising means to apply the brakes automatically, an air-pressure operated contactor having two contacting positions, and a manuhaving two contacting positions, and a manually operable device which when operated permits prevention of an automatic application of the brakes provided the brake-setting means are in their inactive position and the contacter is in one of its contacting positions, said manually operable device also permitting restoration of the brakes provided the contacter is in its other contacting position.

2l. .In a train control system, the combination of -car-carried apparatus and trackway devices cooperating inductively in case of danger conditionsahead, the car-carried apparatus comprising brake-setting means, an air-operated piston having normally balanced pressures on opposite sides, two airoperated contacts actuated by said piston, one normally closed and the other normally open, and an acknowledging device, the acknowledging device preventing tlie automatic application of tlie brakes provided the normally closed air-operated contact has not been opened, such prevention not being possible it the pressure on one side of the piston has dropped below a predetermined amount, and permitting release of the brakes, after an automatic brake application, .only if the other air-operated contact is closed.

In testimony whereof we aiX our signatures.

HARVEY B. MILLER. PHILIP X. RICE. 

